The International Cessna^® 170 Association

Firstly,
Thankyou gentlemen for your imputs,they are greatly appreciated. As an engineer I get too bogged down in the theory side of things and not on the practical side. As stated by jamyst removing the flap under the cowl could be a good thing for me. I will try one at 40 deg and then remove it and see what happens. I
shall have the pressure gauges set up in both chambers also. Its also about drag as engine cooling can be up to a total of 1/3 of total drag. That flap could be causing the air to be come too turbulant and even choke the air exiting the engine cowl.
mick170a ,your very welcome to drop by when In BNE. I shall take you for a fly .This is a great part of the world.

Ghostflyer, will send you a PM for some contact details.. would be good to have a look at your machine.

Regards,

ghostflyer. May I suggest a book called Speed with Economy by Ken Pazer(sp)? There you will find all your answers to the trying questions. It works on a Rotary powered RV-6 and a Wilksh 3cyl. diesel RV-9 as well. It is quicker to travel paths once trodded then to trailblaze through the untrodded forest where dead trees lie.

I read with great interest what Jamyat did with his air outflow outlet on his engine. It would be greatly appreciated Jamyat if you could post a picture of your opening and the diminsions. I have just finished flying my aircraft due to enlarging the exhaust air outlet by 1.5 ins. I was trying to minimise the mean average temperature of the CHT,s.and I had temperatures [CHT.S] of 370 rising to 400 deg. When on descent they would drop to 270 very quickly. I felt this was a range that was too wide. During taxi that the CHT was around 380 deg and during takeoff it peaked around 400 -410. So with a ground temperature of 30deg C , I felt a long hard climb at max power the CHT,s would rise to over 450 deg. Oil temperatures of 190 deg plus also.
After enlarging the outlet and putting a 60deg airflow deflector on it the temperatures now sit at 340-350 degs. Oil temperatures now sit at 170 deg. Due to the density altitude today ,I climbed at 750 ft/min at 70 kts. During the climb the CHT got to 375 deg and oil temp was 180 deg. I leveled off at 4500ft and temperatures stabilized at 360degs and oil temps of 170 degs.
These temperatures are now the same as my Cessna 182 fitted with the Lycoming engine and cowl flaps open.
I descended at 500 ft/min and and rpm at 2200 and the CHT,s .stayed around 320 deg. Am I happy ??? No , I have lost 5 kts of TAS. due to opening up the outflow outlet.More drag. Originally I had great reservations about the coarse pitch[60 ins] on the sensenich prop . It performs great so the pitch stays. The aircraft leaps off the ground.

ghostflyer, I do have some photos that I will attempt to upload, but don't have time now. I have purchased a JPI 701 engine monitor with EGT and CHT. It also has fuel flow capability. I did this because I also bought a set of Gamijectors. After the JPI is installed I will have some data regarding temps.

If one is going to all the work of installing a Lycoming 360 might as well add a supercharger. What's another $9500 and a third bump in the cowling? I wonder how hard it would be to get something like that approved. Looking at all the advantages they claim for a supercharger over a turbocharger why is it that Lyc. and TCM never went this route?

I flew De Haviland Doves, way back when, for a small commuter that repalced he Gypsey Moth engine with Lycomings and super charged them. The modified Dove was one of the most enjoyable airplanes I have had the opportunity to fly. I liked having to ability to adjust the manifold pressure manually, as needed during the climb. Might be a little over kill for the 170. It has always seemed the ideal to me to be able to some how super charge the C-145, O-300 for five minutes as needed. Just a little fantasy I play with.

jamyat, I'm interested in seeing the cowling modification photos as well.
How was the modification approved?

Here are a couple of photos of the cowl. The sheet metal work is not the smoothest I ever saw, but it works. Approval was part of the engine approval, not a separate approval.

Thanks for the photos.
That looks like it really could make a difference in drag.
It would be interesting to see the numbers from a plane Jane 170 with that cowling.

Jamyat,
I notice your original looking wheel pants have fairings covering the brakes, do you have a source for those fairings? Thank you.

...and there is a leading edge fairing on the landing gear.

johneeb,
You asked Jim Yates about his brake covers. Check with John Pugielese, a member, in the directory in California. I believe he used to be involved with them.

These wheel fairings w/brake covers are not specifically for the 170..but are for the 172 (however they do have some approved aftermarket items for 170 aircraft, most of which I laugh at ..but... their nose cowl replacements may be useful... ):
http://www.shopknots2u.com/store.php?cr ... how_detail

John Pugliese had his brake fairings on his '52 C-170B.